Methanol, the simplest of the alcohols, is a highly desirable substance which is useful as a fuel, as a solvent, and as a feedstock in the manufacture of more complex hydrocarbons. In accordance with the method of methanol manufacture that is currently practiced in the petroleum industry, methane is first converted to synthesis gas, a mixture of carbon monoxide and hydrogen. The synthesis gas is then converted over an alumina based catalyst to methanol. The formation of synthesis gas from methane is an expensive process.
As will be apparent, methane and methanol are closely related chemically. Methane comprises a major component of a natural gas and is therefore readily available. Despite the advantages inherent in producing methanol directly from methane, no commercially valuable system for doing so has heretofore been developed.
The present invention comprises a method of and apparatus for manufacturing methanol which overcomes the foregoing and other deficiencies which have long since characterized the prior art. In accordance with the broader aspects of the invention, there is generated a stream of sub-micron sized methane bubbles. Due to their extremely small size, the methane bubbles have an extremely large surface area which increases reaction efficiency. The methane bubbles are entrained in flowing water. Ultraviolet light energy interacting with a titanium-based catalyst forms hydroxyl radicals which cleave the carbon-hydrogen bonds in the methane to form methyl radicals. The methyl radicals combine with the hydroxyl radicals to form methanol.
In accordance with more specific aspects of the invention, a sintered stainless steel tube has an exterior coating comprising a titanium-based catalyst. The stainless steel tube is positioned within a glass tube, and water is caused to continuously flow through the annular space between the two tubes. Methane is directed into the interior of the sintered stainless steel tube and is maintained at a pressure just high enough to prevent the flow of water into the stainless steel tube. As the water passes over the stainless steel tube, methane bubbles are continually stripped off of the sintered surface. The methane bubbles thus generated are sub-micron in size and then therefore present an extremely large surface area.
Ultraviolet light energy generated from ultraviolet lamps is directed through the glass tube and engages the titanium-based catalyst to generate hydroxyl radicals in the flowing water. The hydroxyl radicals cleave the carbon-hydrogen bonds in the methane forming either molecules of hydrogen or molecules of water and methyl radicals. The methyl radicals combine with the hydroxyl radicals to form methanol. Subsequently, the methanol is separated from the water and the other products of the reaction by distillation.